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Publication numberUS4727068 A
Publication typeGrant
Application numberUS 06/790,528
Publication dateFeb 23, 1988
Filing dateOct 23, 1985
Priority dateOct 23, 1985
Fee statusLapsed
Also published asCA1277912C, DE3683612D1, EP0227234A1, EP0227234B1
Publication number06790528, 790528, US 4727068 A, US 4727068A, US-A-4727068, US4727068 A, US4727068A
InventorsMichael Abrams, Beverly Teicher
Original AssigneeJohnson Matthey, Inc.
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Radiosensitization by cobalt and Fe(III) complexes
US 4727068 A
Abstract
Hypoxic cells are rendered more sensitive to destruction by X-rays or other high energy radiation by treatment with cobalt or iron coordination compounds.
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Claims(4)
We claim:
1. A method for rendering hypoxic cells more sensitive to irradiation which comprises subjecting the cells to treatment with a Co(III) or Fe(III) coordination compound selected from the group consisting of:
(1) compounds having the formula:
[CoNn X6-n ]y                               (1)
where
n has a value of 3 or 4;
N is an uncharged nitrogen donor atom that is contained in a ligand;
X represents an anionic ligand; and
y represents the charge on the complex;
(2) compounds having the formula:
[CoA2 Xl D]y.sbsb.1                         (2)
where
A represents a bidentate or tetradentate negative ligand containing N or O donor atoms;
X1 and D represent the same or different monodentate ligands; and
y1 represents a positive or negative charge on the complex;
(3) compounds having the formula:
[CoZ3 ]                                               (3)
where Z represents a chelating mononegative negative ligand; and
(4) compounds of the formula:
[Fe TT1 ]+                                       (4)
where T and T1, which may be the same or different, represent mono-negative tridentate ligands.
2. The method of claim 1 wherein the treatment is carried out before irradiation.
3. The method of claim 2 wherein the compound is
[Co(NH3)4 (NO2)2 ]X where X is NO- 3 or CH3 CO- 2;
[(C2 H5)Fe]CCl3 CO- 2 2 CCl3 CO2 H;
[Co(1,10-phenanthroline)2 (NO2)2 ]NO3 H2 O; or
[Co(diethylene triamine)(NO2)3.
4. A pharmaceutical composition containing a radiosensitizing amount of a Co(III) or Fe(III) coordination compound as described in claim 1.
Description

The present invention relates to radiosensitization and, more particularly, to rendering hypoxic cells more sensitive to being killed by X-rays or other forms of irradiation.

BACKGROUND TO THE INVENTION

One established form of cancer treatment is irradiation by high-energy electromagnetic waves, typically X-rays. Solid tumors contain significant numbers of cells which are distal from the vasculature leading to oxygen deficiency or hypoxia. Hypoxia protects cells from radiotherapy. There is, therefore, a need for compounds which render the hypoxic cells more sensitive to killing by X-rays or the like. These compounds will be referred to herein as "radiosensitizers".

A variety of transition metal complexes have been shown to possess radiosensitizer activity. These include complexes of Ag, Cu, Zn, Hg, Pt, Co, Fe and Rh--1-13. The present invention is based on the finding that certain coordination compounds of cobalt and iron, namely Co(III) and Fe (III) coordination compounds, are potentially useful as radiosensitizers.

DESCRIPTION OF THE INVENTION

More particularly, the Co(III) or Fe(III) compounds contemplated for use herein may be selected from (1) compounds having the formula:

[CoNn X6-n ]y                               (1)

where

n has a value of 3 or 4;

N is an uncharged nitrogen donor atom that is contained within a ligand;

X represents an anionic ligand; and

y represents the charge on the complex;

(2) compounds having the formula:

[CoA2 X1 D]y.sbsb.1                         (2)

where

A represents a bidentate or tetradentate negative ligand containing N or O donor atoms;

X1 and D represent the same or different monodentate ligands; and

y1 represents a positive or negative charge on the complex;

(3) compounds having the formula:

[CoZ3 ]                                               (3)

where Z represents a chelating mononegative negative ligand; and

(4) compounds of the formula:

[Fe TT1 ]+                                       (4)

where T and Tl, which may be the same or different, represent mono-negative tridentate ligands.

Typically, when L is an uncharged nitrogen donor ligand, it is ammonia, mono-or-di-alkylamine, a heterocyclic ring such as substituted or unsubstituted pyridine, imidazole or aziridine.

L may also be a chelating diamine such as ethylenediamine, 1,10-phenanthroline and 2,2'-bipyridine, triamines such as diethylenetriamine and 1,4,7-triazacylononane, and tetramines such as triethylenetetramine.

Representative values for X include nitrate, nitrite, sulphate, halide, thiocyanate, azide, cyanide, acetate, malonate or oxalate.

As noted, y represents the charge on the complex and usually is +1 or 0. Where y is +1, the compound includes a complex cation and the counter ion may be halide, sulphate, nitrate or other like anion.

With respect to the compounds of formula (2), representative examples of A include dimethylglyoxime and any B-diketonate such as acetylacetone (acac). The A substituent can also be a tetradentate dinegative ligand of the Schiff base variety: ##STR1##

X' and D, which may be the same or different monodentate ligands, can be charged or uncharged. Typical examples of these substituents include pyridine, nitrite, halide, aziridine, substituted imidazole, alkyl amine and the like.

Where y1 is negative, the compound includes a complex anion and the counter ion may be selected from ammonium, sodium, potassium or the like. Where y1 is positive, the compound includes a complex cation and the counter ion may be selected from halide, sulphate, or other like anions.

As for compounds (3), Z may be, inter alia, an amino acid or a B-diketonate.

T and T1, in the case of the compounds (4), represent mono-negative, tridentate ligands such as cyclopentadienyl, substituted cyclopentadienyl, hydro-tris (pyrazoyl) borate, alkyl-tris (pyrazolyl) borate and substituted analogs of the indicated borates.

Specific examples of compounds which may be used as sensitizers according to the invention include the following:

Co(NH3)3 X3 where X is NO2 - or CN-

[Co(1,10-phenanthroline)2 X2 ]NO3 where X is NO2 -, CN- or halide

[Co(aziridine)4 (NO2)2 ]Br

[Co(ethylenediamine)2 X2 ]X where X is NO2 - or halide

[Co(DH)2 (pyridine)Cl]where DH stands for the anion of dimethylglyoxime

[Co(DH)2 (aziridine)2 ]Cl

Co(glycine)3

Co(2,4-pentandionato)3

[Co(pentanedionato)2 (NO2)(pyridine)

Co(dien)(NO2)3 where dien is diethylenetriamine

[Fe(C2 H5)2 ]X where X is an anion such as a halide, NO3 -, CCl3 CO2

[Fe(HB(PYZ)3)]X where HB(PYZ)3 is hydrotris pyrazolylborate

The above compounds are known and their preparation is shown in the chemical literature.

The invention contemplates not only the use of the above noted categories of compounds for use as radiosensitizers but pharmaceutical compositions for such use including the indicated compounds as the effective radiosensitizing agent, together with a pharmaceutically-acceptable solid or liquid carrier, diluent or excipient therefor. These compositions may take any of the conventional forms for effective administration, e.g. pills, tablets, sterile injectable solutions and the like, containing an effective amount of one or more of the indicated compounds of formulas (1) to (4). Usually the amount of such compound or compounds contained in such compositions will fall in the range of 0.1 to 5% by weight or even more (e.g. 20%), based on the total weight of the composition.

The indicated composition may be used in conventional manner for radiosensitizing purposes in combination with irradiation or the like in the treatment of cancer. Preferably the compound is administered before irradiation in the usual amounts to effect radiosensitization although the administration may also occur concurrently with the radiation.

Radiosensitizers for use according to the invention may be evaluated in toxicity and radiosensitization screens. The toxicity screen is used to evaluate the cytotoxicity of the compound itself. The method of testing is as follows:

Cells--The EMT6 mammary tumor cell line is well established and has been widely used for the study of hypoxic cells. See Laboratory Animal Science 27:831-851 (1977). These experiments were performed using asynchronous EMT6-BT monolayers in exponential growth in Waymouth's medium supplemented with antibiotics and 15% newborn calf serum. This cell line has a plating efficiency of 65-80% and a doubling time of 16-19 hrs. in vitro. See J. Natl. Cancer Inst. 49:735-474 (1972). The cells begin to show a measurable reduction in survival from hypoxic stress alone after approximately 8-9 hr in a hypoxic atmosphere. See Radiat. Res., 53:281-294 (1973).

Radiosensitization Studies--To produce hypoxia, plastic flasks, containing exponentially-growing monolayers in complete medium plus serum, were fitted with sterile rubber septums and exposed to a continuously-flowing 95% nitrogen/5% CO2 humidified atmosphere for 4 hr at 37 C. Parallel flasks were maintained in 95% air/5% CO2. At the end of 4 hr, the drug or vehicle was added to the flasks by injection through the rubber septum without disturbing the hypoxia. A drug dose of 100 μM was selected to produce minimal toxicity from the drug alone under the conditions of the experiments. Oxic or hypoxic conditions were maintained throughout the 1 hour drug exposure at 37 C. and the irradiation was obtained using a cesium 137 irradiation unit at a dose rate of approximately 1.05 Gy/min. at 25 C. Drug treated cells were irradiated so that the irradiation would be completed 1 hour after addition of the drug. X-ray doses of 500, 1000, 1500 and 2000 rads were used. After treatment, the monolayers were washed with sterile phosphate buffered saline. The cells were suspended by trypsinization, counted with a counter, then diluted with complete medium. Three different volumes of the cell suspension were plated in duplicate on dishes containing complete medium. Dishes were incubated for 8-10 days under standard cell culture conditions to allow clonogenic cells to grow into macroscopic colonies. The colonies were visualized by staining with crystal violet in methanol containing 3.7% formaldehyde and were counted manually. Each experiment was repeated three times.

Baseline curves for irradiation of the cells under oxic and hypoxic conditions in the absence of the compounds were also determined to allow a quantitative estimation of the efficiency of the compound in sensitizing the cells to radiation-induced killing. This quantification may be expressed in the form of an enhancement ratio calculated from the slope of the survival curve in the presence of the compound divided by the slope of the survival curve in the absence of the compound.

Cytotoxicity--To measure cytotoxicity, varying concentrations of drug (50, 100 and 500 μM) was added to exponentially growing EMT6 cells maintained under hypoxic conditions or oxygenated conditions. After 1 hr, cells were washed, suspended and plated as described above. Correction for cell killing due to hypoxia was made in the hypoxic cell survival curve. As in the single time exposure experiments, each cytotoxicity time course experiment was repeated three times.

The invention is illustrated by the following examples:

EXAMPLE 1

Preparation of trans-[Co(NH3)4 (NO2)2 ]X where X is NO3 - or CH3 CO2 - from G. S. Schessinger, "Inorganic Laboratory Preparations" Chemical Publishing Company, Inc., N.Y., 1962, P. 246.

A solution of CoCl2 6H2 O (18.0 g) in water (50 mL) was prepared and added to a solution of NH4 Cl (20.0 g), NaNO2 (27.0 g), and concentrated aqueous ammonia (20 mL) in water (150 mL). Air was bubbled through this solution for 4 hrs. and the reaction mixture was allowed to stand in the dark overnight. The yellow product was collected and washed with cold water (310 mL). This material was added to a hot (60 C.) solution of acetic acid (1 mL) in water (400 mL). After being stirred for 5 min., the solution was filtered and NH4 NO3 was added to the filtrate. The resulting yellow crystalline product was collected, washed with cold water (15 mL), ethanol (20 mL) and either (20 mL) and dried in vacuo. Yield=11.4 g of trans-[Co(NH3)4 (NO2)2 ]NO3.

The acetate salt can be prepared by using NH4 CH3 CO2 instead of NH4 NO3 in the last step.

Analysis of acetate salt:

______________________________________    C          H      N______________________________________% Calc.    8.67         5.44   30.22% Found    8.42         5.47   29.95______________________________________
EXAMPLE 2

This example describes the preparation of [(C2 H5) Fe]CCl3 CO2 - 2CCl3 CO2 H according to D.N. Hendrickson et al., J. Chem. Phys. 58, 1973, 4666.

Ferrocene (3.0 g) and trichloroacetic acid (7.9 g) were dissolved in benzene (50 mL). Air was bubbled through the solution for 1 hr. and then the solution was stoppered and placed in a refrigerator (5 C.) overnight. The product was collected, washed with benzene (10 mL) and dried in vacuo.

Analysis :

______________________________________    C          H      N______________________________________% Calc.    28.46        1.79   47.25% Found    28.19        1.81   47.52______________________________________
EXAMPLE 3

This example illustrates the preparation of cis-[Co(1,10-phenanthroline)2 (NO2)2 ]NO3 H2 O according to A. V. Ablov, Russ. J. Inorg. Chem., 6, 1961, 157.

To a solution of Co(NO3)2 6H2 O (2.9 g) and NaNO2 (3.0 g) in water (40 mL) was added a solution of phenanthroline hydrate (3.9 g) in ethanol (20 mL). A small quantity (0.5 mL) of acetic acid was added and the reaction mixture was stirred for 10 min. The product was collected and recystallized from hot water containing an excess of NaNO3. Yield

Analysis :

______________________________________    C          H      N______________________________________% Calc.    47.30        3.31   16.09% Found    47.04        3.31   16.01______________________________________
EXAMPLE 4

The products of Examples 1 to 3 may be checked for radiosensitization and cytotoxicity using the procedure outlined above under the heading "Radiosensitization Studies", and "Cytotoxicity". Administration of the compounds followed by irradiation as described shows a very marked reduction in the survival fraction of hypoxic cells as well as oxic cells. The compounds may thus be effectively used as radiosensitizers in combination with irradiation.

It will be recognized that various modifications may be made in the invention as described above. Accordingly, the scope of the invention is defined in the following claims.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3017325 *Dec 29, 1955Jan 16, 1962David A VogelTherapeutic composition for topical application and method of applying the same
US4569932 *Mar 5, 1984Feb 11, 1986University Of Northern Iowa FoundationsLow toxicity radiation sensitizer
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4851403 *Apr 21, 1987Jul 25, 1989Johnson Matthey, Inc.Radiation sensitizers
US5371234 *Sep 23, 1992Dec 6, 1994The Unites States Of America As Represented By The Secretary Of CommerceIon specific chelating agents derived from β-hydroxyhistidine, 4-(1-hydroxy-1-alkyl)imidazole and derivatives thereof
US6057453 *Sep 30, 1999May 2, 2000Florida State UniversityPharmaceutical compounds comprising polyamines substituted with electron-affinic groups
US6060604 *Sep 30, 1996May 9, 2000Florida State UniversityPharmaceutical compounds comprising polyamines substituted with electron-affinic groups
US6255495Mar 27, 2000Jul 3, 2001Florida State UniversityPharmaceutical compounds comprising polyamines substituted with electron-affinic groups and method of application thereof
US7875602Jan 25, 2011Sutter West Bay HospitalsCamptothecin derivatives as chemoradiosensitizing agents
US8563537Jul 29, 2008Oct 22, 2013Sutter West Bay HospitalCamptothecin derivatives as chemoradiosensitizing agents
US8691261Jul 18, 2012Apr 8, 2014Ihi CorporationDrug, drug guidance system, magnetic detection system, and drug design method
US8779138Jan 24, 2011Jul 15, 2014Sutter West Bay HospitalCamptothecin derivatives as chemoradiosensitizing agents
US20060217291 *Jan 24, 2006Sep 28, 2006Ichiro HirotsuRadiosensitizer
US20070093432 *May 30, 2006Apr 26, 2007California Pacific Medical CenterCamptothecin derivatives as chemoradiosensitizing agents
US20080318873 *Jul 29, 2008Dec 25, 2008California Pacific Medical CenterCamptothecin derivatives as chemoradiosensitizing agents
US20090169484 *Jun 26, 2008Jul 2, 2009Ihi CorporationIron-salen complex
US20110184009 *Jul 28, 2011Sutter West Bay Hospitals, Dba California Pacific Medical CenterCamptothecin derivatives as chemoradiosensitizing agents
DE19646762A1 *Nov 4, 1996May 7, 1998Schering AgWell tolerated diagnostic agent or radio-sensitiser
DE19646762B4 *Nov 4, 1996May 13, 2004Schering AgVerwendung von Metallverbindungen zur Herstellung von Mitteln zur Strahlentherapie von Tumoren
EP1704870A1 *Jan 24, 2006Sep 27, 2006Nipro CorporationUse of iron compounds as radiosensitizers
WO1999056828A1 *Apr 30, 1999Nov 11, 1999Christoph HehrleinCatheter or vessel support with radiation sensitizer and corresponding production method
Classifications
U.S. Classification514/184, 514/188, 514/185, 548/101
International ClassificationC07F15/04, A61P35/00, C07F15/02, A61K31/28, A61K33/26, A61K33/24
Cooperative ClassificationA61K33/24, A61K33/26
European ClassificationA61K33/26, A61K33/24
Legal Events
DateCodeEventDescription
Feb 13, 1986ASAssignment
Owner name: DANA-FARBER CANCER INSTITUTE, INC. MASSACHUSETTS A
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:TEICHER, BEVERLY A.;REEL/FRAME:004508/0068
Effective date: 19860205
Feb 24, 1986ASAssignment
Owner name: JOHNSON MATTHEY INC., MALVERN PA 19355
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:ABRAMS MICHAEL;REEL/FRAME:004512/0122
Effective date: 19860128
Aug 20, 1991FPAYFee payment
Year of fee payment: 4
Oct 3, 1995REMIMaintenance fee reminder mailed
Feb 25, 1996LAPSLapse for failure to pay maintenance fees
May 7, 1996FPExpired due to failure to pay maintenance fee
Effective date: 19960228